From 43a915a7d0280d8cea632c768fee1b9dfb5e7fcd Mon Sep 17 00:00:00 2001
From: Pawel Wieczorkiewicz <wipawel@amazon.de>
Date: Mon, 8 Feb 2021 14:01:04 +0100
Subject: [PATCH] lib: add write_cr0() and enable_sse() helper functions

Signed-off-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
---
 include/lib.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/lib.h b/include/lib.h
index 4d32c2ff..63c24028 100644
--- a/include/lib.h
+++ b/include/lib.h
@@ -28,6 +28,7 @@
 #include <asm-macros.h>
 #include <console.h>
 #include <ktf.h>
+#include <processor.h>
 #include <segment.h>
 
 #define min(a, b)                                                                        \
@@ -232,6 +233,10 @@ static inline unsigned long read_cr0(void) {
     return cr0;
 }
 
+static inline void write_cr0(unsigned long cr0) {
+    asm volatile("mov %0, %%cr0" ::"r"(cr0));
+}
+
 static inline unsigned long read_cr2(void) {
     unsigned long cr2;
 
@@ -395,6 +400,11 @@ static inline unsigned long ipow(int base, unsigned int exp) {
     return result;
 }
 
+static inline void enable_sse(void) {
+    write_cr0((read_cr0() & ~X86_CR0_EM) | X86_CR0_MP);
+    write_cr4(read_cr4() | X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT);
+}
+
 /* External declarations */
 
 extern void halt(void);